When terrorists kill civilians or captives, it “significantly lowers the likelihood of bargaining success,” they state.

Abrahms, an expert on insurgency and terrorism at Northeastern University in Boston, told The Jerusalem Postthat the study builds on his previous work that shows statistically that militant groups are less likely to achieve their demands when they physically harm civilians.

“In the aforementioned study, we show that terrorism doesn’t pay in the context of hostage situations. Specifically, hostage-takers are less likely to successfully pressure government compliance when civilians are harmed in the course of the hostage crisis. Hostage- takers have better success at the bargaining table when they refrain from harming the captives, especially when they are not civilians,” he said.

Terrorist attacks against civilians tend to backfire politically on the perpetrators, while “violence against military forces – like Hezbollah’s 1983 guerrilla attacks against the American and French peacekeepers in Lebanon – are more likely to coerce government concessions,” he said.

Therefore, Abrahms says, “militant groups should abstain from targeting civilians in order to maximize the chances of government concessions. In this sense, terrorism does not pay.”

Furthermore, the authors found that contrary to popular wisdom, democracies are more resilient against terrorism than previously thought.

Despite the belief that “their commitment to civil liberties inhibits them from adopting sufficiently harsh countermeasures and their low civilian cost tolerance limits the capacity to withstand attacks,” democracies actually are less likely to give in to terrorist demands, it said.

The study breaks terrorist demands into two categories: political and material.

Political demands include the removal of foreign troops or a change in the makeup of the government, while material demands refer to the release of prisoners or economic benefits.

Islamic terrorists often make what seem to outsiders as unrealistic demands because the terrorists see them as sacred, but are able to claim victory if they are even partially met.

“Bin Laden’s 1998 fatwa, for example, called on the United States to withdraw from the Middle East. This demand remains unmet, of course, but al-Qaida may deem the smaller concession of withdrawing from Saudi Arabia five years later as an important victory in itself,” state Abrahms and Gottfried.

However, because terrorists often refuse “to compromise on their maximalist strategic demands,” it lowers their odds of success.

"It depends on what ones definition of success is. There have been very few tangible, long term gains for terrorists," Steven David, an international relations expert from Johns Hopkins University told the Post.

"On the other hand, they have gained publicity for their cause and a sense of belonging for alienated youth," he said adding that he thinks the Palestinians "would have gained much more through nonviolent resistance."

Jonathan Schanzer, vice president for research at the Foundation for Defense of Democracies, told the Post that this excellent study contributes to an important debate, but offers a few caveats.

“The Gilad Schalit deal was an example where terrorism did pay. His kidnapping led to Israel’s release of an unprecedented number of prisoners,” said Schanzer.

“In places like North Africa and Yemen, al-Qaida affiliate groups have also successfully deployed the kidnap- and-ransom model to refill their coffers. European nations have been willing time and again to acquiesce to the demands of these groups,” he said.

Ely Karmon, senior researcher at the Institute for Counter-Terrorism at the Interdisciplinary Center Herzliya’s Institute for Policy and Strategy, told the Post, “The authors’ conclusion: ‘In short, the analysis does not support the position that terrorism pays’ is not true as a rule or thesis.”

For example, he said, “Fatah with the help of other organizations, especially the PFLP, has succeeded through the use of terrorism to achieve the building of a Palestinian national identity, ‘honor,’ and the recognition of legitimacy by the Arab states and most of the states in the UN.”

The success of terrorism was enhanced because of the support of Arab states, he said.

Furthermore, Hamas, Palestinian Islamic Jihad, and Hezbollah with the support of Iran, have used terrorism to sabotage the peace process with the Palestinians, said Karmon, pointing out that it was former prime minister Yitzhak Rabin who said terrorism was a strategic threat to the peace process.

Karmon makes this argument in detail in an article titled “The Iran-Palestine Linkage,” in which he says that world powers should deal not only with the Iranian nuclear issue, but also with its support for terrorism in negatively impacting the Palestinian- Israeli conflict.